Emi shielding gasket

ABSTRACT

Provided is an electromagnetic interference shielding gasket, which includes an elastomer, a soldering prevention part disposed in at least one region of a side surface and a bottom surface of the elastomer, and an electrode disposed on the bottom surface of the elastomer. Even when solder cream for attaching the EMI shielding gasket to a printed circuit board is pushed from the bottom surface of the EMI shielding gasket by its surface tension and solder-rising, the solder cream stays in the soldering prevention part without moving upward along the side surface of the EMI shielding gasket. Accordingly, the reliability of soldering can be ensured without sacrificing elastic resilient force of the EMI shielding gasket.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No.10-2010-0100439 filed on Oct. 14, 2011 and all the benefits accruingtherefrom under 35 U.S.C. §119, the contents of which are incorporatedby reference in their entirety.

BACKGROUND

The present disclosure relates to an electromagnetic interference (EMI)shielding gasket, and more particularly, to an EMI shielding gasket fora surface mount technology (SMT).

Electromagnetic waves may be emitted outward from a circuit ofelectronic devices through the atmosphere, or be transmitted through anelectric wire. Various electromagnetic waves generated from a circuit ofan electronic device may degrade the performance of peripheralelectronic devices, make noise with peripheral electronic devices,damage an image formed by peripheral electronic devices, decrease theservice life of peripheral electronic devices, and cause a defect inperipheral electronic devices. Furthermore, such electromagnetic wavesmay affect human bodies.

EMI shielding gaskets are used to address these issues. EMI shieldinggaskets are disposed within a gap of a panel, a terminal, or a case ofelectronic devices such as mobile phones, LCD monitors, and computers,to prevent electromagnetic waves from being emitted from the electronicdevices. As electronic devices are miniaturized, EMI shielding gasketsmay be attached through surface mount on a printed circuit board (PCB).Such EMI shielding gaskets for a surface mount technology are requiredto have high electrical conductivity, excellent soldering properties,high heat resistance, and excellent elastic resilient characteristics.

To mount an EMI shielding gasket on a printed circuit board throughsurface mount, solder cream is applied to the EMI shielding gasket,then, the EMI shielding gasket is positioned to contact the printedcircuit board, and then, a reflow process is performed. At this point,the solder cream is melted to have low viscosity, and is moved up to aportion of the side surface of the EMI shielding gasket by its surfacetension and solder-rising during the reflow process, and thus, theportion of the side surface of the EMI shielding gasket is soldered.

In this case, since the soldered portion of the EMI shielding gasket isfixed, elasticity of the soldered portion is decreased, and thus,elastic resilient force of the EMI shielding gasket is entirelydecreased. Thus, the thickness of an electronic product may be increasedaccording to a decreased amount of the elastic resilient force of theEMI shielding gasket.

In addition, when the solder cream is moved up to the portion of theside surface of the EMI shielding gasket, and the portion of the sidesurface is soldered, the amount of solder cream between the printedcircuit board and the bottom surface of the EMI shielding gasket isreduced, and thus, the EMI shielding gasket comes off the printedcircuit board, thereby causing a defect such as soldering failure. Toaddress these issues, the amount of the solder cream is increased, andthus, its costs are increased.

SUMMARY

The present disclosure provides an EMI shielding gasket that ensureselastic resilient force even after surface mount.

The present disclosure also provides an EMI shielding gasket thatprevents solder cream from moving upward along a side surface of the EMIshielding gasket, thereby preventing the side surface from beingsoldered.

The present disclosure also provides an EMI shielding gasket, whichincludes a trench or recess in at least one region of side and bottomsurfaces of an elastomer, or a soldering prevention layer on the sidesurface, to prevent solder cream from moving upward along a side surfaceof the EMI shielding gasket, thereby preventing the side surface frombeing soldered.

In accordance with an exemplary embodiment, an electromagneticinterference shielding gasket includes: an elastomer; a solderingprevention part disposed in at least one region of a side surface and abottom surface of the elastomer; and a conductive layer disposed in atleast one region of the elastomer.

The electromagnetic interference shielding gasket may further include ahole that passes through the elastomer from a front surface of theelastomer to a rear surface thereof.

The soldering prevention part may include a stepped part disposedbetween the side surface and the bottom surface of the elastomer. Thesoldering prevention part may include a trench disposed in at least oneof the side surface and the bottom surface of the elastomer. Thesoldering prevention part may include at least one recess disposed in atleast one of the side surface and the bottom surface of the elastomer.

The soldering prevention part may include: a stepped part disposedbetween the side surface and the bottom surface of the elastomer; and atrench and at least one recess in at least one of the side surface andthe bottom surface of the elastomer.

The soldering prevention part may include a soldering prevention layerdisposed on at least one side surface of the elastomer.

The conductive layer may be disposed at least on the bottom and sidesurfaces of the elastomer, and be formed by adhering a conductivematerial with a conductive adhesive tape.

The conductive layer may be formed by applying paste formed of aconductive material.

The conductive layer may be partially inserted and fixed in theelastomer, and be bent along the front, rear, and bottom surfaces of theelastomer.

The conductive layer may include: a fixing part disposed in the hole; aconnecting part bent downward from the fixing part along the front andrear surfaces of the elastomer; and a contact part bent from theconnecting part along the bottom surface of the elastomer.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments can be understood in more detail from thefollowing description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1A is a perspective view illustrating an electromagneticinterference (EMI) shielding gasket in accordance with an exemplaryembodiment;

FIG. 1B is a front view illustrating the EMI shielding gasket of FIG.1A;

FIG. 1C is a bottom view illustrating the EMI shielding gasket of FIG.1B;

FIG. 2A is a perspective view illustrating an EMI shielding gasket inaccordance with another exemplary embodiment;

FIG. 2B is a front view illustrating the EMI shielding gasket of FIG.2A;

FIG. 3A is a perspective view illustrating the upper portion of an EMIshielding gasket in accordance with another exemplary embodiment;

FIG. 3B is a front view illustrating the EMI shielding gasket of FIG.3A;

FIG. 3C is a perspective view illustrating the lower portion of the EMIshielding gasket of FIG. 3B;

FIG. 4A is a front view illustrating an EMI shielding gasket inaccordance with another exemplary embodiment;

FIG. 4B is a side view illustrating the EMI shielding gasket of FIG. 4A;

FIG. 4C is a cross-sectional view illustrating the EMI shielding gasketof FIG. 4B;

FIG. 5A is a perspective view illustrating an EMI shielding gasket inaccordance with another exemplary embodiment;

FIG. 5B is a front view illustrating the EMI shielding gasket of FIG.5A;

FIG. 6A is a perspective view illustrating an EMI shielding gasket inaccordance with another exemplary embodiment;

FIG. 6B is a front view illustrating the EMI shielding gasket of FIG.6A;

FIG. 7A is a perspective view illustrating an EMI shielding gasket inaccordance with another exemplary embodiment;

FIG. 7B is a front view illustrating the EMI shielding gasket of FIG.7A;

FIG. 8A is a perspective view illustrating an EMI shielding gasket inaccordance with another exemplary embodiment;

FIG. 8B is a front view illustrating the EMI shielding gasket of FIG.8A;

FIG. 9A is a perspective view illustrating an EMI shielding gasket inaccordance with another exemplary embodiment; and

FIG. 9B is a front view illustrating the EMI shielding gasket of FIG.9A.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, specific embodiments will be described in detail withreference to the accompanying drawings. The present invention may,however, be embodied in different forms and should not be construed aslimited to the embodiments set forth herein. Rather, these embodimentsare provided so that this disclosure will be thorough and complete, andwill fully convey the scope of the present invention to those skilled inthe art.

FIG. 1A is a perspective view illustrating an electromagneticinterference (EMI) shielding gasket in accordance with an exemplaryembodiment. FIG. 1B is a front view illustrating the EMI shieldinggasket of FIG. 1A. FIG. 1C is a bottom view illustrating the EMIshielding gasket of FIG. 1B.

Referring to FIGS. 1A, 1B and 1C, the EMI shielding gasket includes anelastomer 100 and a conductive layer 200. A hole 110 passes through theelastomer 100 from the front surface of the elastomer 100 to the rearsurface thereof. Stepped parts 120 are disposed between the bottomsurface of the elastomer 100 and the side surfaces thereof. Theconductive layer 200 is disposed on the bottom surface of the elastomer100.

For example, the elastomer 100 may have a rectangular parallelepipedshape with square front and rear surfaces and rectangular side, top, andbottom surfaces. Alternatively, the elastomer 100 may be round from aportion of the side surfaces to the top surface, but is not limitedthereto. In the current embodiment, the square surfaces through whichthe hole 110 passes are defined as the front and rear surfaces of theelastomer 100, and the rectangular surfaces disposed at both sides ofthe hole 110 are defined as the side surfaces of the elastomer 100.However, the directivities of the front, rear, and side surfaces are notlimited thereto. For example, the directivities of the front, rear, andside surfaces may be determined with respect to the conductive layer200. The elastomer 100 may be formed of a material having predeterminedelasticity. For example, the elastomer 100 may include: a polymersynthetic resin such as polyurethane foam, polyvinyl chloride (PVC),silicone, ethylene vinylacetate copolymer, and polyethylene; rubber suchas natural rubber (NR), styrene butadiene rubber (SBR), ethylenepropylene diene monomer (EPDM) rubber, nitrile butadiene rubber (NBR),and neoprene; solid sheets; or a sponge sheet. However, the elastomer110 is not limited thereto, and thus, may be formed of any elasticmaterial. The elastomer 100 may have shock and vibration absorbingproperties, surface resistivity, and vertical volume resistivity. Theelastomer 100 may be conductive or non-conductivity. When the elastomer100 is conductive, the elastomer 100 may include carbon black, graphite,gold, silver, copper, nickel, or aluminum. These materials may be formedon the surface of the elastomer 100, or be contained in the elastomer100. That is, the elastomer 100 formed in advance may be coated with aconductive material, or the elastomer 100 may be formed of a mixture ofan elastic material and conductive fine powder. The hole 110 may passthrough the elastomer 100 from the front surface of the elastomer 100 tothe rear surface thereof. The hole 110 improves the shock and vibrationabsorbing properties and elasticity of the elastomer 100. The hole 110may have an approximately circular shape, or a tetragonal shape, but isnot limited thereto. Since the elastomer 100 has elasticity, the hole110 may be removed. The elastomer 100 may be provided with solderingprevention parts that prevent solder cream from moving upward along theside surfaces of the EMI shielding gasket in a reflow process forsurface mount. The soldering prevention parts may be provided by formingthe stepped parts 120 between the bottom surface of the elastomer 100and the side surfaces thereof. Accordingly, even though a portion ofsolder cream is pushed by its surface tension toward both sides of theconductive layer 200 in a reflow process, the solder cream is collectedin spaces defined by the stepped parts 120, and thus, the solder creamis prevented from moving upward along the side surfaces of the EMIshielding gasket. Accordingly, the solder cream is prevented from beingsoldered to the side surfaces of the EMI shielding gasket, therebypreventing elastic resilient force of the EMI shielding gasket frombeing decreased.

The conductive layer 200 is disposed on the bottom surface of theelastomer 100 where the EMI shielding gasket contacts a printed circuitboard. That is, the conductive layer 200 may be disposed entirely on thebottom surface of the elastomer 100 except for the stepped parts 120 andthe middle of the bottom surface of the elastomer 100 as illustrated inFIGS. 1A, 1B and 1C. The conductive layer 200 may be formed of aconductive material including a metal such as aluminum, copper, nickel,gold, and silver, or be formed by adhering a conductive adhesive tape(not shown) to the elastomer 100. Alternatively, the conductive layer200 may be formed by applying conductive paste including a metal. Inthis case, while the elastomer 100 is formed through injection molding,the conductive layer 200 may be formed from the conductive paste.

As described above, the EMI shielding gasket includes the stepped parts120 between the bottom surface and the side surfaces of the elastomer100 to prevent solder cream from moving upward along the side surfacesof the EMI shielding gasket in a reflow process for surface mount. Thatis, since solder cream pushed by its surface tension stays at thestepped parts 120, the solder cream is prevented from moving upwardalong the side surfaces of the EMI shielding gasket. Accordingly, thesolder cream is prevented from being soldered to the side surfaces ofthe EMI shielding gasket, thereby preventing elastic resilient force ofthe EMI shielding gasket from being decreased. In addition, since thesolder cream is soldered at the stepped parts 120, the EMI shieldinggasket may be fixed more securely. The soldering prevention parts forpreventing solder cream from being soldered to the side surfaces of theEMI shielding gasket may vary in shape and position, and an electrode tobe described later may vary in shape and position. With respect to this,EMI shielding gaskets will now be described in accordance with variousexemplary embodiments.

FIG. 2A is a perspective view illustrating an EMI shielding gasket inaccordance with another exemplary embodiment. FIG. 2B is a front viewillustrating the EMI shielding gasket of FIG. 2A.

Referring to FIGS. 2A and 2B, the EMI shielding gasket includes trenches130 in the bottom surface of an elastomer 100. For example, a conductivelayer 200 may extend in the longitudinal direction of the elastomer 100in the middle of the bottom surface of the elastomer 100, and thetrenches 130 may be disposed out of the conductive layer 200. Thetrenches 130 may extend along the conductive layer 200, and have apredetermined depth from the bottom surface of the elastomer 100.Accordingly, solder cream stays in the trenches 130 during a reflowprocess, and thus, the solder cream is prevented from being soldered tothe side surfaces of the elastomer 100.

FIG. 3A is a perspective view illustrating the upper portion of an EMIshielding gasket in accordance with another exemplary embodiment. FIG.3B is a front view illustrating the EMI shielding gasket of FIG. 3A.FIG. 3C is a perspective view illustrating the lower portion of the EMIshielding gasket of FIG. 3B. Referring to FIGS. 3A, 3B and 3C, recesses140 are disposed in the bottom surface of an elastomer 100. One of therecesses 140 may be disposed in the bottom surface of the elastomer 100out of a conductive layer 200, or the recesses 140 may be spaced apredetermined distance from each other in the bottom surface of theelastomer 100. The recesses 140 may have a predetermined shape such as acircular or tetragonal shape. Accordingly, solder cream stays in therecesses 140 during a reflow process, and thus, the solder cream isprevented from being soldered to the side surfaces of the elastomer 100.

FIG. 4A is a front view illustrating an EMI shielding gasket inaccordance with another exemplary embodiment. FIG. 4B is a side viewillustrating the EMI shielding gasket of FIG. 4A. FIG. 4C is across-sectional view illustrating the EMI shielding gasket of FIG. 4B.

Referring to FIGS. 4A, 4B and 4C, the EMI shielding gasket includes anelastomer 100 and a conductive layer 200. A hole 110 passes through theelastomer 100 from the front surface of the elastomer 100 to the rearsurface thereof. Stepped parts 120 as soldering prevention parts aredisposed in at least one region between the bottom surface of theelastomer 100 and the side surfaces thereof. The conductive layer 200passes through the hole 110 of the elastomer 100, is fixed to andsupported by the elastomer 100, and extends down to the bottom surfaceof the elastomer 100 along the side surfaces of the elastomer 100.

The elastomer 100 may be formed of an elastic material such that thehole 110 passes through the elastomer 100 from the front surface to therear surface, and the stepped parts 120 are disposed between the bottomsurface and the side surfaces. The stepped parts 120 prevent soldercream from moving upward along the side surfaces of the EMI shieldinggasket in a reflow process for surface mount.

The conductive layer 200 passing through the hole 112 is exposed out ofthe elastomer 110, and exposed portions of the conductive layer 200 arebent along the front, rear, and bottom surfaces of the elastomer 100.That is, the conductive layer 200 includes a fixing part 210 disposed inthe hole 110 of the elastomer 100, a plurality of connecting parts 220bent downward from both ends of the fixing part 210 along the front andrear surfaces of the elastomer 100, and a plurality of contact parts 230bent from ends of the connecting parts 220 along the bottom surface ofthe elastomer 100. The contact parts 230 contact and are fixed throughsurface mount to a device such as a printed circuit board. The fixingpart 210 is disposed in the elastomer 100 to fix the conductive layer200, thereby preventing a removal of the conductive layer 200 from theelastomer 100. The connecting parts 220 connect the fixing part 210 tothe contact parts 230. Although the conductive layer 200 is divided intothe fixing part 210, the connecting parts 220, and the contact parts230, the fixing part 210, the connecting parts 220, and the contactparts 230 may be integrally formed of the same material. The conductivelayer 200 may be formed of a conductive material with a predeterminedwidth. The fixing part 210 inserted in the hole 110 has a width equal toor smaller than the diameter of the hole 110. The connecting parts 220and the contact parts 230 disposed out of the hole 110 may have a widthequal to the width of the elastomer 110 except for the stepped parts120. The conductive layer 200 may be formed of a conductive materialincluding a metal such as aluminum, copper, nickel, gold, and silver.Alternatively, the conductive layer 200 may be formed by plating a fibersheet with a metal, to thereby have flexibility.

FIG. 5A is a perspective view illustrating an EMI shielding gasket inaccordance with another exemplary embodiment. FIG. 5B is a front viewillustrating the EMI shielding gasket of FIG. 5A. Referring to FIGS. 5Aand 5B, trenches 130 may be disposed in the lower portions of the sidesurfaces of an elastomer 100. The trenches 130 may extend in a straightline shape in the longitudinal direction of the elastomer 100. As such,when the trenches 130 are disposed in the side surfaces of the elastomer100, solder cream moving upward along the side surfaces of the elastomer100 in a reflow process stays in the trenches 130 and is hardened. Thus,the EMI shielding gasket is fixed at a portion of the side surfaces ofthe elastomer 100 as well as at the bottom surface of the elastomer 100,thereby attaching the EMI shielding gasket more securely. In this case,if the trenches 130 are disposed at a height equal to or greater thanthat of the hole 110, elastic resilient force of the EMI shieldinggasket may be reduced. Thus, the trenches 130 are disposed lower thanthe hole 110.

FIG. 6A is a perspective view illustrating an EMI shielding gasket inaccordance with another exemplary embodiment. FIG. 6B is a front viewillustrating the EMI shielding gasket of FIG. 6A. Referring to FIGS. 6Aand 6B, one or more recesses 140 are disposed in the side surfaces of anelastomer 100. One of the recesses 140 may be disposed in the sidesurface of the elastomer 100 along a conductive layer 200, or therecesses 140 may be spaced a predetermined distance from each other inthe side surface of the elastomer 100. The recesses 140 may have apredetermined shape such as a circular or tetragonal shape.

In accordance with the above embodiments, the soldering prevention partare provided by forming at least one of the stepped parts 120, thetrenches 130, and the recesses 140 in at least one region of the sideand bottom surfaces of the elastomer 100. Alternatively, referring toFIGS. 7A and 7B, soldering prevention layers 150 may be formed on theside surfaces of an elastomer 100 to prevent solder cream from movingupward along the side surfaces of the elastomer 100. The solderingprevention layers 150 may have a thickness ranging from approximately0.01 mm to approximately 0.2 mm, and be formed of one of aheat-resistant polymer layer, a flexible heat-resistant polymer tape,and a heat-resistant elastic coating material such as polyimide Teflon,Teflon tape, or silicone rubber. In this case, when the solderingprevention layers 150 are disposed on the side surfaces of the elastomer100, the stepped part 120, the trench 130, or at least one of therecesses 140 may be disposed in the bottom surface of the elastomer 100.

In accordance with the above-described embodiments, the conductive layer200 is disposed on the bottom surface of the elastomer 100, and thesoldering prevention part is disposed in at least one region of theelastomer 100. Alternatively, a conductive layer 200 may surround anelastomer 100. That is, referring to FIG. 8, the conductive layer 200may be disposed on at least one portion of the bottom and side surfacesof the elastomer 100, or be disposed on all of the surfaces of theelastomer 100 including the front, rear, bottom, and top surfacesthereof. To form the conductive layer 200, a conductive materialincluding a metal such as aluminum, copper, nickel, gold, and silver maybe adhered to the elastomer 100 through an adhesion member such as anadhesive tape, or a conductive adhesion tape including a conductivematerial may be adhered to the elastomer 100. Alternatively, theconductive layer 200 may be formed by applying conductive pasteincluding a metal to surround the elastomer 100. In this case, while theelastomer 100 is formed through injection molding, the conductive layer200 may be formed from the conductive paste. Alternatively, referring toFIG. 9, a first conductive layer 200 may be disposed on at least oneportion of an elastomer 100 including a portion of the bottom and sidesurfaces of the elastomer 100, and a second conductive layer 220 may bedisposed under the bottom surface of the elastomer 100. That is, if onlythe first conductive layer 200 is disposed on the elastomer 100, asurface mount process may be incompletely performed. To improvereliability of the surface mount process, the second conductive layer220 may be disposed under the bottom surface of the elastomer 100.

In accordance with the embodiments, at least one trench or recess isdisposed in at least one of the bottom and side surfaces of theelastomer. In addition, the soldering prevention layer such as siliconerubber may be disposed on at least one of the bottom and side surfacesof the elastomer.

In accordance with the embodiments, even when solder cream for attachingthe EMI shielding gasket to a printed circuit board is pushed from thebottom surface of the EMI shielding gasket by its surface tension andsolder-rising, the solder cream stays in the trench or recess withoutmoving upward along the side surface of the EMI shielding gasket, or isprevented from moving upward by the soldering prevention layer.Accordingly, the reliability of soldering can be ensured withoutsacrificing the elastic resilient force of the EMI shielding gasket. Inaddition, since solder cream is soldered to fix a portion of the sidesurfaces of the EMI shielding gasket, the EMI shielding gasket can befixed more securely.

Although the EMI shielding gasket has been described with reference tothe specific exemplary embodiments, it is not limited thereto.Therefore, it will be readily understood by those skilled in the artthat various modifications and changes can be made thereto withoutdeparting from the spirit and scope of the present invention defined bythe appended claims.

1. An electromagnetic interference shielding gasket comprising: anelastomer; a soldering prevention part disposed in at least one regionof a side surface and a bottom surface of the elastomer; and aconductive layer disposed in at least one region of the elastomer. 2.The electromagnetic interference shielding gasket of claim 1, furthercomprising a hole that passes through the elastomer from a front surfaceof the elastomer to a rear surface thereof.
 3. The electromagneticinterference shielding gasket of claim 1, wherein the solderingprevention part comprises a stepped part disposed between the sidesurface and the bottom surface of the elastomer.
 4. The electromagneticinterference shielding gasket of claim 1, wherein the solderingprevention part comprises a trench disposed in at least one of the sidesurface and the bottom surface of the elastomer.
 5. The electromagneticinterference shielding gasket of claim 1, wherein the solderingprevention part comprises at least one recess disposed in at least oneof the side surface and the bottom surface of the elastomer.
 6. Theelectromagnetic interference shielding gasket of claim 1, wherein thesoldering prevention part comprises: a stepped part disposed between theside surface and the bottom surface of the elastomer; and a trench andat least one recess in at least one of the side surface and the bottomsurface of the elastomer.
 7. The electromagnetic interference shieldinggasket of claim 6, wherein the soldering prevention part comprises asoldering prevention layer disposed on at least one side surface of theelastomer.
 8. The electromagnetic interference shielding gasket of claim1, wherein the soldering prevention part comprises a solderingprevention layer disposed on at least one side surface of the elastomer.9. The electromagnetic interference shielding gasket of claim 1, whereinthe conductive layer is disposed at least on the bottom and sidesurfaces of the elastomer, and is formed by adhering a conductivematerial with an adhesive member.
 10. The electromagnetic interferenceshielding gasket of claim 1, wherein the conductive layer is formed byapplying paste formed of a conductive material.
 11. The electromagneticinterference shielding gasket of claim 2, wherein the conductive layeris partially inserted and fixed in the elastomer, and is bent along thefront, rear, and bottom surfaces of the elastomer.
 12. Theelectromagnetic interference shielding gasket of claim 11, wherein theconductive layer comprises: a fixing part disposed in the hole; aconnecting part bent downward from the fixing part along the front andrear surfaces of the elastomer; and a contact part bent from theconnecting part along the bottom surface of the elastomer.